Consumers prefer white surfaces, and white regions of multi-coloured surfaces, to remain white after many cycles of cleaning. Thus, ‘whiteness maintenance’ is an important benefit associated with fabric treatment compositions. In a fabric treatment composition, this typically involves washing or otherwise treating fabrics with compositions comprising ingredients designed to assist in soil removal and suspension, but also ingredients designed to improve the whiteness perception of fabrics through optical effects such as fluorescent brighteners and fabric hueing agents. Fluorescent brighteners typically enhance whiteness perception by imparting a bluish hue to textiles through absorption of UV light and re-emission as violet or blue light which counteracts textile yellowness arising, for example, from fabric damage or soils. Hueing agents enhance whiteness perception through a different mechanism involving depositing hueing agents onto surfaces to effect disproportionate absorption of visible light. This skews the fabric reflectance spectrum leading to a violet or bluish tint. However, with this hueing agent mechanism, since coloured substances deposit onto the surface, there is an overall reduction in fabric reflectance which leads to a dulling effect. This can be particularly noticeable under poor lighting conditions. This can be compensated to some degree by use in combination with fluorescent brighteners but even then, in indoor lighting conditions the dulling effect may still be significant. Furthermore, hueing agents may give products containing them unwanted product colouration. This may be a particular problem in liquid products, particularly compact (concentrated) or super-compact liquid laundry detergents and unit dose detergents, especially those comprising liquids or gels in a water-soluble pouch, and rinse-added treatment compositions. In these forms, consumers may be concerned that strongly coloured products may cause unwanted staining. The present invention mitigates one or more of these problems.